1. Field of the Invention
The present application claims priority under Paris convention on the basis of Japanese patent application No. 2005-220085 filed on Jul. 29, 2005, and cites entire contents referred from said patent application.
The present invention relates to a portable information terminal device, more specifically improvement of a portable information terminal device which carries out an authentication process on the basis of photographed images.
2. Description of the Related Art
Portable information terminal devices such as mobile phones include devices provided with a camera for generating image data by photographing an object. The camera is provided with a photoelectric conversion element such as, for example, a CCD (Charge-Coupled Device) or CMOS (Complementary Metal Oxide Semiconductor) image sensor.
In some of the portable information terminal devices of this kind distributed to the market recently, an authentication process (so-called face authentication) is carried out by guiding a user to photograph a face image by a camera during operation and comparing characteristic information such as a shape and size of eyes, nose, mouth and outline extracted from a photographed face image with user characteristic information which is stored in advance in a memory provided in the portable information terminal devices. Only when results of an authentication process show that a matching degree between characteristic information extracted from a photographed image and user characteristic information exceeds an authentication threshold value, a person who carries out operation at that time is determined to be a true user and authorized to execute processes thereafter, so that security improvement and privacy protection can be enhanced (ex. refer to Patent Document 1).
In the authentication process, a power is initially supplied to a camera so as to start the camera, where an initialization process of a photographic conversion element provided in the camera is carried out, so that the camera is allowed to photograph an object. When it is made possible to photograph the object by the camera, an image of the object with respect to the camera is displayed in real time in a display part provided in the portable information terminal device. A person who carries out operation makes adjustments so as to photograph a face of the person by the camera while looking at a display screen (i.e. finder screen) in the display part, and carries out determination operation so as to photograph a face image. Therefore, characteristic information is extracted from a photographed face image, and the characteristic information is compared with user characteristic information stored in advance in order to realize an authentication process.    [Patent Document 1] Japanese Unexamined Patent Publication No. 2000-278658